Combination refrigerating appliance and evaporators for same

ABSTRACT

The refrigerating appliance comprises at least one first, second and third refrigerating area for a low, medium or high storage temperature, whereby each refrigerating area has an evaporator ( 24, 25, 26 ). The refrigerating appliance also comprises a compressor ( 19 ), a refrigerant circuit for supplying compressed refrigerant to the evaporators ( 24, 25, 26 ) and for returning expanded refrigerant to the compressor ( 19 ), and comprises at least one switching element ( 22, 22 ′) for directing, as desired, the refrigerant through one of two branches (I, II) of the refrigerant circuit. In the first branch (I), the evaporators ( 24, 26 ) of the first and the third refrigerating areas are connected in series. In the second branch (II), The evaporators ( 24, 25, 26 ) of all three refrigerating areas are connected in series.

TITLE OF THE INVENTION

The present invention relates to a refrigerating appliance with at leastthree refrigerating areas and evaporators for such a refrigeratingappliance.

(2) Description of Related Art

Such a refrigerating appliance is disclosed in DE 4 242 776 A1.

This known refrigerating appliance has two valve units located in therefrigerant circuit and may be activated, in order to channel arefrigerant flow only through an evaporator dedicated to the firstrefrigerating area called a refrigeration compartment, or subsequentlythrough an evaporator dedicated to the second refrigerating areadescribed as standard refrigeration compartment and the refrigerationcompartment evaporator or through a third evaporator dedicated to arefrigerating area described as freezer compartment and therefrigeration compartment evaporator. This means that the refrigeratingappliance has three operating modes, a first in which only therefrigeration compartment is cooled, a second, in which the standardrefrigeration compartment and the refrigeration compartment are jointlycooled, and a third, in which the freezer compartment and therefrigeration compartment are jointly cooled. The operating times mayvary considerably within the three operating modes. Since the chillingdepartment has a relative weak insulation and a small evaporator whencompared to the other compartments, the operating time in the thirdoperating mode may clearly exceed that of the second. This leads to ahigh overall operating time of the refrigerating machine of therefrigeration appliance and therefore to a high-energy consumption andto a lower temperature of the refrigeration compartments than necessary.

BRIEF SUMMARY OF THE INVENTION

The object of the invention is to define a refrigerating appliance andevaporators for a refrigerating appliance which enables a reduction ofthe operating time in the third operating mode and thereby preventsuper-cooling the refrigeration compartment and reduce the energyconsumption of the refrigerating appliance.

By connecting the evaporators of all three refrigerating areassequentially in the second branch of the refrigerant circuit of therefrigerating appliance or by placing the connections on the evaporatorsso that a series connection of the three evaporators spans between twoof the connections will be achieved that the third refrigerating area,the freezer compartment, will also be cooled when the refrigerant flowis routed over the second refrigerating area, the standard refrigerationcompartment. The freezer compartment is therefore also continuouslycooled when cooling the standard refrigeration compartment, so that theoperating time required to adhere to the holding temperature of thefreezer compartment is reduced in the third operating mode and thereforealso the overall cooling period of the refrigeration compartment.

On the other hand, in order to now avoid excessive cooling of thefreezer compartment at the expense of the refrigeration compartment, aneffective provision may be made so that the second branch of therefrigerant circuit extends only over a section of the surface of theevaporator of the freezer compartment. The size of this section toobtain adequate cooling in all refrigerating areas at minimum powerconsumption depends on the sections of the individual evaporators and/oron their cooling capacities, as well as on the insulation quality of theindividual temperature sectors. A generally effective rule for the sizeof this surface section can therefore not be defined; however, asuitable value is adjustable per experiment without any difficulty.

The evaporator of the third refrigerating area may be arranged in thesecond branch between the evaporators of the first and the secondrefrigerating area, so that the evaporated refrigerant partially flowsthrough while the maximum cooling capacity per surface unit of theevaporator accumulates in the particular refrigerating area which iscirculated by the refrigerant which is still in a liquid state.

Appropriately, the refrigerant circuit further has a third branch, whichonly contains the evaporator of the first refrigerating area. This thirdbranch may be used when the cooling capacity, which reaches the firstrefrigerating area over the first or the second branch, is insufficientto maintain its holding temperature.

In this case, it may be appropriate that the first and the second branchexpand over only a section each of the evaporator surface of the firstrefrigerating area. If this method assures that the cooling capacitywhich the first and the second branch in the first refrigerating areadevelop is somewhat insufficient to adhere their holding temperature, sothat occasionally an operation of the third branch is required, asuper-chilling of the first temperature section and the thereforeaccompanying dissipation of energy is therefore impossible.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Additional characteristics and advantages of the invention result fromthe description of implementation examples in the following withreference to the added figures, in which:

FIG. 1 shows a perspective of a household refrigeration appliance withthree temperature areas for which the submitted invention is applicable,

FIG. 2 shows the refrigeration system of the refrigeration appliance inFIG. 1 in a simplified, schematic illustration, and

FIGS. 3 and 4 show examples of evaporators for the refrigerationappliance corresponding with the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a perspective of a household refrigeration appliance 10,whereof the heat-insulated housing 11 is provided with attached anddoors 12–14 which open separately at its opening at the edge of theopening edge. Three compartments, which are superimposed and thermallyseparated by partitions in the interior of the housing 11, are lockableby the doors 12–14 which form the refrigerating areas 15–17 for variousstorage temperatures. The upper refrigerating area which may be lockedby door 12 represents a refrigeration compartment, centre section 16,which is assigned to the door 13, serves as standard refrigerationcompartment, while the section 17 located below is designed as freezercompartment and can be locked with the door 14. The various storagetemperatures in the individual sections are maintained with theassistance of the refrigeration system described in the following.

The refrigeration system 18 illustrated schematically in FIG. 1 has arefrigerant compressor 19 behind which a condenser 20 is located on thepressure side. A dehumidifier cartridge 21 connects to the outlet of thecondenser 20, whose outlet is connected with the inlet of a first valveunit 22, which is designed as an electromagnetically operated 3/2 wayvalve. A first outlet of this valve unit is connected to an inlet of anevaporator 26, which is located in the freezer compartment 17 of therefrigeration appliance. A second outlet of the valve unit 22 isconnected to the inlet of a similar second valve unit 22′, whose twooutlets are always connected with an inlet of an evaporator 25 of thestandard refrigeration compartment 16 and/or an evaporator 24 ofrefrigeration compartment 15. A spirally wound restrictor 23 which isdesigned as capillary tube is connected in series between the inlet ofone of the evaporators 24, 25, 26 and the assigned outlet of a valveunit 22.

The outlet of the evaporator 25 is connected by a connecting linebetween the inlet of the evaporator 26 and the restrictor 23, which isassigned to it, the outlet of the evaporator 26 is connected in ananalog mode with the inlet of the evaporator 24.

The refrigerant circuit therefore has three branches, which are definedas FIG. 1–111. All three branches pass through the evaporator 24, whichis assigned, to the refrigeration compartment 15. The branch in guidesthe refrigerant initially through the evaporator 26 of the freezercompartment 17; branch 111 represents a series connection of all threeevaporators in sequence 25, 26, 24.

A temperature sensor 27, 27′ and 28 is assigned to each compartment 15,16, 17, whereby, as illustrated schematically in the figure, this may bean optionally installed air temperature sensor 27, 27′ in the case ofthe refrigeration compartment 16 and freezer compartment 17, while thesensor 28 is assigned to the surface of the evaporator 24 in the case ofthe refrigeration compartment 14.

A regulator assembly 30 controls the operation of the compressor 19, aswell as the switch position of 22, 22′ by means of measuring signalstransmitted over the signal lines 29 by the sensors 27, 27′, 28.

The regulator assembly 30 moves the refrigerant flow through branch IIby means of the measuring signal of the air temperature sensor 27 of thestandard refrigeration compartment 16, so that the temperature in thestandard refrigeration compartment 16 is at a value set by the user.When a refrigerant flows through this circuit, the freezer compartment17 and the refrigeration compartment 15 are also cooled in addition tothe standard refrigeration compartment 16. The cooling capacities of theindividual evaporators 24, 25, 26 are calculated so that the coolingcapacity of the evaporators 24, 26 are insufficient to cover the coolingrequirement of its compartments 15, 17 during the thermostat-controlledoperation of branch II by means of the measuring signal of sensor 27.

When one of the temperature sensors 27, 28 detects a coolingrequirement, however, the sensor 27 does not, the regulator assembly 30will always operate the refrigeration system in the switch position ofthat for branch 1 or 111.

When the air temperature sensor 27 of standard cooling compartment 16and one of the air temperature sensors 28, 27′ simultaneously detect acooling requirement, arrangements may be made so that the regulatorassembly 30 ignores the detected result of the air temperature sensor 28or 27′ until the air temperature sensor 27 no longer reports a coolingrequirement. This means that all three compartments are cooled until thestandard refrigeration compartment 16 has reached the holdingtemperature and subsequently continues to cool over one of the branches1, 111 depending on the requirement. Alternative arrangements may bemade so that the regulator assembly 30 also considers the deviation ofthe temperature recorded by the air temperature sensor 28 or 27′ of theholding temperature in such an event for the appropriate compartment 15or 17 and that it changes occasionally to branch I or 111, if thedeviation of the measured temperature is greater than that of the airtemperature sensor 27 from the measured holding temperature for theappropriate compartment than depending on the fact if the excessivetemperature is present in the freezer compartment 17 or in the freezercompartment 15, and subsequently again activates the branch when theexcessive temperature deviation has been eliminated.

FIG. 3 shows a first example of an evaporator in a schematicillustration for the refrigerating appliance described in reference toFIGS. 1 and 2. The evaporator contains the abovementioned evaporators24, 25, 26, which are illustrated here assembled on a single supportplate, however, which may also be designed as separate components.

The branch II enters the evaporator 25 of the freezer compartment at aninlet 31 and meanders essentially over its entire surface to a junction32 on the evaporator 26 of the freezer compartment. The line coming fromthe evaporator 25 joins with branch I at this point, which enters theevaporator 26 over an entry connection 33 and from there essentiallyprogresses over the entire surface of the evaporator 26. The linefinally reaches a connecting point 34 on the evaporator 24 of therefrigeration compartment and from there progresses to an outlet 35 overwhich the refrigerant is returned to the compressor 19.

The line between the connecting point 34 and the outlet 35 cools only apart of the surface of the evaporator 24, a line, which progresses froman inlet 36 of the evaporator 24 to the connecting point 34 and belongsto branch III, uses the remaining surface. Through suitable selection ofthe position of the connecting point 34 on the evaporator 24, it may bedefined how large the part of the surface of the evaporator 24 is whichis also a part of the branches I and II and therefore is also cooledalong with the standard refrigeration compartment 16 and freezercompartment 17. The cooling capacity in the refrigeration compartment 15and the hazard of super-cooling of the refrigeration compartment may belimited by this design method during the operation of branches I and II.

The evaporators in FIG. 4 differ from those in FIG. 3 by the position ofthe first connecting point 32. In the case of FIG. 4, this is arrangedat about half the length of the refrigerant line of the evaporators 26so that the evaporator 26 of the freezer compartment is only cooled overits entire surface during the operation of branch I, however, only atabout half during the operation of branch II. The same deliberationsapply here as illustrated in reference to FIG. 3 for the evaporator 24of the refrigeration compartment: The cooling capacity of the evaporator26 may be limited during the operation of branch II by a suitablepositioning of the connecting point 32 and thus avoid super-cooling ofthe freezer compartment during the operation of circuit II. Such ahazard may otherwise develop when the refrigerating appliance isoperated at low ambient temperatures.

1. A refrigerating appliance, comprising: at least a first, a second anda third refrigerating area, having respectively a low, an average and/ora high storage temperature; each of said first, second and thirdrefrigerating areas, having a respective evaporator; a compressor and arefrigerant circuit to supply compressed refrigerant to said evaporatorsand returned expanded refrigerant to said compressor; said refrigerantcircuit including at least two branches and at least one switchingelement to guide said refrigerant through one of said two branches; saidevaporators of said first and third refrigerating areas are sequentiallyconnected in a first one of said two branches; said evaporators of saidfirst, second and third refrigerating areas are sequentially connectedin the second one of said two branches; and said second refrigerantcircuit branch only extends over a portion of the surface of saidevaporator of said third refrigerating area.
 2. A refrigeratingappliance, comprising: at least a first, a second and a thirdrefrigerating area, having respectively a low, an average and/or a highstorage temperature; each of said first, second and third refrigeratingareas, having a respective evaporator; a compressor and a refrigerantcircuit to supply compressed refrigerant to said evaporators andreturned expanded refrigerant to said compressor; said refrigerantcircuit including at least two branches and at least one switchingelement to guide said refrigerant through one of said two branches; saidevaporators of said first and third refrigerating areas are sequentiallyconnected in a first one of said two branches; said evaporators of saidfirst, second and third refrigerating areas are sequentially connectedin the second one of said two branches; said refrigerant circuitincluding a third branch including only said evaporator of said firstrefrigerating area; and said first and said second refrigerant circuitbranches only extend over a portion of the surface of said evaporator ofsaid first refrigerating area.